Disc Check Valve

ABSTRACT

A valve for controlling the flow of a fluid through a fluid passage such that a fluid flow in the fluid passage is permitted in a first direction and restricted in a second direction, wherein the valve comprises a modular valve body composed of a two-piece assembly including an inlet body half and an outlet body half joined along a joint interface, the inlet body half and said outlet body half each comprising interchangeable end connections.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of pending application Ser. No.11/337,822, filed Jan. 23, 2006, which is a continuation-in-part patentapplication of U.S. Pat. No. 6,988,510 issued Jan. 24, 2006 which claimsthe benefit of provisional application No. 60/366,590, filed Mar. 22,2002, the disclosure of each of which are hereby incorporated byreference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to check valves. More particularly, thisinvention relates to check valves for fluids employing a free-floatingdisc that allows fluid flow in an unchecked direction with a minimalincrease in fluid pressure and turbulence while maximizing the rate offluid flow through the valve.

2. Description of the Background Art

Presently, there exist many types of disc valves that employ afree-floating disc that seats in a checked direction of fluid flow andunseats in an unchecked direction. Optimal designs of disc valves seekto minimize the increase in fluid pressure in the unchecked fluid flowdirection, minimize turbulence within the valve and maximize the rate offluid flow through the valve. It is an object of this invention toprovide an improvement that is a significant contribution to theadvancement of the disc valve art.

Another object of this invention is to provide a disc valve having amaximum fluid flow rate.

Another object of this invention is to provide a disc valve having aminimal dimensional package size.

Another object of this invention is to provide a disc valve having aminimal tendency of the seal disc to stick in the open or closedposition.

Another object of this invention is to provide a disc valve having aminimal seal disc deformation under differential pressure loads.

Another object of this invention is to provide a disc valve havingminimal fluid turbulence through the valve.

Another object of this invention is to provide a disc valve having highdifferential seal pressures.

Another object of this invention is to provide a disc valve having ahigh ultimate burst pressure.

Another object of this invention is to provide a disc valve having animproved kinematic action of the seal disc.

Another object of this invention is to provide a disc valve composed ofmodular components to enable various assemblies of end connections.

Another object of this invention is to provide a disc valve having animproved ergonomic design of the valve body/housing.

Another object of this invention is to provide a disc valve having asimplicity of components.

Another object of this invention is to provide a disc valve capable ofbeing consistently and durably manufactured/molded and assembled at alow manufactured cost.

Another object of this invention is to provide a disc valve that isparticularly suited for liquid applications, but that may be employed inlimited gas media applications.

Another object of this invention is to provide a disc valve that isparticularly suited for human blood and blood products applications.

The foregoing has outlined some of the pertinent objects of theinvention. These objects should be construed to be merely illustrativeof some of the more prominent features and applications of the intendedinvention. Many of the beneficial results can be attained by applyingthe disclosed invention in a different manner or modifying the inventionwithin the scope of the disclosure. Accordingly, other objects and afuller understanding of the invention may be had by referring to thesummary of the invention and the detailed description of the preferredembodiment in addition to the scope of the invention defined by theclaims taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

For the purposes of summarizing this invention, the invention comprisesa free-floating disc type check valve that out-performs similar,competitive valve designs and offers a wide variety of customer desiredend connections not readily offered by competitive disc valvemanufacturers. The valve was designed specifically for liquidapplications, however limited gas media applications are possible withthe design. Utilization of the valve for human blood and blood productsapplications is also intended with this design.

One embodiment of the present invention is directed toward a valve forcontrolling the flow of a fluid through a fluid passage such that afluid flow in the fluid passage is permitted in a first direction andrestricted in a second direction. The valve includes a valve body havingan internal fluid chamber with internal side walls. A valve member iscontained in the internal fluid chamber. The valve member is a freefloating disc-shaped check valve having a first side with an attachedtruncated torroidal shaped portion and a relatively flat second side. Anarray of finger-shaped projections are positioned on the valve body thatreceive the valve member when fluid is flowing through the valve in thefirst direction. The finger-shaped projections are positioned a distanceaway from the internal side walls of the valve body such that thedisc-shaped check valve is held in the center portion of the valve bodyby the finger-shaped projections thereby facilitating fluid flow aroundthe outside edges of the disc-shaped check valve. In addition, thefinger-shaped projections are dimensioned to receive the truncatedtorroidal shaped portion of the disc-shaped check valve such that fluidis allowed to flow between the finger-shaped projections. The valve bodyconsists of an inlet portion and an outlet portion that are designed tosealing couple together to form the valve body. The inlet portion of thevalve body has an annular sealing protrusion such that when a fluidattempts to flow in the second direction the annular sealing protrusionand the flat portion of the disc-shaped check valve couple to create aseal against the fluid flow in the second direction. In a preferredembodiment, the valve member is constructed of a single piece ofelastomeric material, the inlet portion of the valve body is constructedfrom a single piece of plastic and the outlet portion of the valve bodythat includes the finger-shaped projections is constructed from a singlepiece of plastic. Furthermore, the valve body is preferably constructedfrom a clear plastic that allows the operation of the valve to bevisually monitored.

The above described valve offers a number of improvements over the priorart. First, the finger like projections restrict the movement of thevalve member in the valve body and significantly reduce the likelihoodthat the valve member will become jammed in the open or closed position.In addition, the truncated torroidal structure adds rigidity to thevalve member that keeps it from bending or becoming stuck when sealingthe valve in response to a fluid flow in the restricted directionthrough the valve. Finally, the simplistic construction and operation ofthe valve decreases the costs associated with use of the valve. Thus,the above described embodiment offers a number of improvements in theprior art.

Another embodiment of the present invention is directed toward a valvefor preventing fluid from flowing in one direction through a fluidchannel. The valve includes a valve member having a sealing side portionand a flow side portion wherein the sealing side portion issubstantially flat and the flow side portion is substantiallycup-shaped. A valve body contains the valve member. The valve member isconstructed from a single piece of elastomeric material coated with anon-stick material that minimizes friction between the valve member andvalve body. The valve body has a valve member receiving section that isconfigured to receive the flow side portion of the valve member whenfluid is flowing through the valve such that fluid flows throughopenings in the valve member receiving section. The valve memberreceiving section includes a plurality of projections positioned suchthat an opening exists between each projection and such that the valvemember is centered within the valve body when received by the valvemember receiving section. Preferably, the plurality of projections arefinger-shaped and arranged in an substantially circular configuration.In such an embodiment, the flow side portion of the valve member is thenreceived inside of the substantially circular projection configurationwhen fluid is flowing through the valve such that the fluid flows aroundthe outside edges of the valve member and between the plurality ofprojections.

Yet another embodiment of the present invention is directed toward amethod of preventing fluid from flowing through a pipe in one direction.The method commences by positioning a valve body in the pipe.Preferably, the valve body is constructed out of a transparent materialsuch that proper operation of the valve can be visually confirmed. Afree floating valve member is then enclosed inside of the valve body.The valve member is configured to create a hydrodynamic sealing force onthe valve member when fluid attempts to flow through the pipe in theflow-inhibited direction. The valve member is engaged with aflow-through seal member having finger-like projections such that it iscentered in the valve body when fluid is flowing through the pipe in theflow allowed direction. The free floating valve member is engaged with aflow-inhibiting seal member when fluid is attempting to flow through thepipe in the flow-inhibited direction.

The above described embodiments improve upon the prior art by using thefinger-like projections to center the valve member in the valve bodysuch that the flow rate is maximized and the failure rate due to thevalve member becoming stuck is minimized. In addition, configuring thevalve member to create a hydrodynamic sealing force helps move the valvemember from the open position to the closed position while insuring thatit does not become stuck. The use of a transparent construction allows auser to visually inspect the valve to determine if it is properlyoperating. Thus, the above described method offers a number ofadvantages over the prior art.

The foregoing has outlined rather broadly the more pertinent andimportant features of the present invention in order that the detaileddescription of the invention that follows may be better understood sothat the present contribution to the art can be more fully appreciated.Additional features of the invention will be described hereinafter whichform the subject of the claims of the invention. It should be greatlyappreciated by those skilled in the art that the conception and thespecific embodiment disclosed may be readily utilized as a basis formodifying or designing other methods for carrying out the same purposesof the present invention. It should also be realized by those skilled inthe art that such equivalent methods do not depart from the spirit andscope of the invention as set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more succinct understanding of the nature and objects of theinvention, reference should be directed to the following descriptiontaken in conjunction with the accompanying drawings in which:

FIG. 1 is a cross-sectional view of the assembled disc valve of theinvention;

FIG. 2 is a cross-sectional view of the downward flow portion of thedisc valve of the invention;

FIG. 3 is an end view of FIG. 2;

FIG. 4 is a cross-sectional view of the disc of the disc valve of theinvention;

FIG. 5 is an end view of FIG. 4;

FIG. 6 is a cross-sectional view of the assembled disc valve of theinvention with male and female luer lock fittings;

FIG. 7 is a cross-sectional view of the assembled disc valve of theinvention with luer fittings;

FIG. 8 is a cross-sectional view of the assembled disc valve of theinvention with male luer lock fittings;

FIG. 9 is a cross-sectional view of the assembled disc valve of theinvention with a female luer lock fittings;

FIG. 10 is a cross-sectional view of the assembled disc valve of theinvention with tube and male luer lock fittings;

FIGS. 11 and 12 is a cross-sectional view of the assembled disc valve ofthe invention with tube and male luer lock fittings; and

FIG. 13 is a diagram showing the flow rates of the disc valve of theinvention as compared to several prior art disc valves.

Similar reference numerals refer to similar parts throughout the severalfigures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A. Seal Disc Configuration and Function:

As shown in FIGS. 1-5, the new disc check valve utilizes a unique sealdisc 12, employing a specific geometry to accomplish multiple specificfunctions in operation. The configuration of the seal disc 12 may bedescribed as a flat circular disc 14 integrally mated to a modified,truncated torroidal shape 16 projecting from the downward-flow surfaceof the disc 12. The torroidal shape 16 is the key element of the designof the seal disc 12. This geometry provides the following functionalfeatures:

1. The cylindrical mass of the torus 16 on one side of the disc 12imparts structural rigidity to the seal, helping to keep the sealsurface 18 of the disc 12 flat with respect to the annular seal 20 ofthe valve body 22. The torus 16 shape is positioned so as to have itsmass over the annular seal 20. Deflection of the valve seal disc 12, andultimate leakage or failure, is minimized under higher differentialpressures. “Compression set”, or permanent deformation of the valve sealdisc 12 is mitigated by the structural stiffness added by the torroidalshape 16, and flexural deformation in transition between open and closedpositions of the valve seal 12 are minimized. This helps to prevent“sticking” or locking of the valve seal 12 in the open or closedposition evidenced in traditional check valves utilizing a common flatdisc seal.

2. The torroidal shape 16 is designed to work in conjunction with“fingers” or projections 24 inside the valve body 22. These projections24 loosely surround the periphery of the torus 16 limiting the lateraldisplacement of the seal disc 12 in relation to the annular seal 20 ofthe valve body 22. The projections 24 are designed to permitpredetermined axial travel of the valve seal disc 12 to the openposition permitting fluid flow through the valve body 22. The specificprofile of the periphery of the torus 16 is also designed to allowangular displacement of the seal disc 12 with respect to the centerlineaxis of the valve assembly 10, while preventing the seal disc 12 frombecoming wedged or entrapped in the open position with the “fingers” orprojections 24. In this arrangement, the axial displacement of the sealdisc 12 and annular clearance between the circumference of the valveseal disc 12 and the annular seal 20 of the valve body 22 is maximized,along with the annular area between the seal disc 12 and the valve bodyinternal wall 26. The outer profile of the torroidal shape 16 alsofunctions cooperatively with the internal valve body shape to directfluid flow transitionally into the convergent orifice of the valve bodyoutlet 28 when the disc 12 is in the open position, as discussed furtherin section “Valve Performance, Flow and Pressure”.

3. The “cup” shape formed by the modified torus 16, and bounded on oneaxial end by the flat disc shape, forms a piston 30 that takes advantageof liquid flow moving from the distal toward the proximal end of thevalve interior and uses the hydrodynamic force of the liquid to assistin moving the seal disc 12 from the open to the closed position. Thevelocity of the fluid is higher in proximity to the center axis of thevalve assembly 10 as is the fluid pressure, due to the projections 24,or “fingers”, surrounding the annular seal 20 directing the larger massof fluid flow into the “cupped” section 30 of the seal disc 12. Thisacts to make the valve assembly 10 more quickly responsive todifferential pressure to close the valve.

Seal disc 12 may be integrally formed of silicone, low density siliconeor polyisoprene or other appropriate elastomeric material. All candidatematerials are USP class VI and have notable chemical andbiocompatibility properties, as well as structural properties.Elastomeric material hardness offers the optimal balance betweenstructural stiffness and material compression is required to effect asuitable seal in contact with the annular seal 20 of the valve body 22.Fabrication of the polyisoprene material is usually limited tocompression molding and, owing to the cost of the material and themanufacturing process, realizes a significantly higher production costversus the silicone material. The silicone material may be eithercompression molded or liquid injection molded, (LIM). Low densitysilicone may be used in very low pressure environments to achieve afloating effect as well being functional in inverted positions where thedisc 12 would need to be “lifted” by the fluid flow to a closedposition. Production costs and quantities are inversely proportionalbetween compression and liquid injection molding processes, with LIM,offering the higher production quantity with the lower cost per part.Tooling costs for the LIM process are much higher than the compressionmethod however.

Both materials for the valve seal 12 may be coated with Parylene N,which functions as a dry film lubricant. This acts to reduce thebreakaway friction, or “stiction” of the valve seal 12 from the valvebody annular sealing 20, thereby greatly reducing the valve openingactivation force, (pressure), required. The Parylene coating alsofunctions a lubricant to act in conjunction with the outside profile ofthe torroidal shape 16 of the disc seal 12 in contact with theprojections or “fingers” 24 inside the valve body 22. The shape of thedisc valve 12, coupled with the Parylene coating insures that the valveseal will be prevented from sticking or mechanically “locking” in theopen position. Evaluation of uncoated silicone seal discs, demonstratedthat the seal disc adheres to the valve body seat when dry and leftstatic for 24 hours or less. Pressure required to dislodge the seal discvaried from 0.5 PSI to 2.0 PSI. Test valves with uncoated silicone sealdiscs that were left for 24 hours in the open position also demonstratedthat the seal disc adheres to the “fingers” inside the valve body.Although more easily dislodged than seals that were left closed, thiseffect clearly demonstrates the benefit of the Parylene coating inhelping to prevent valve failures and enhancing valve performance.

B. Valve Body Configuration and Function:

The valve body 22 is designed as a two-piece assembly comprising aninlet body half 22I and an outlet body half 22O. Both body halves arejoined at a midline, perpendicular to the centerline flow axis of thevalve. The joint interface is an overlapping “L” shape 32 that providesfor either solvent bonding, or sonic welding of the two valve bodycomponents.

Operation of the valve is integral with the interior cavity formed bythe two body halves 22 and the seal disc 12. This internal cavity isspecifically shaped to allow smooth fluid flow transitions from theinlet to the outlet, and minimize turbulence. Residual volume andcollection of residual fluid in the valve interior is reduced viagenerous radii at flow vector transitions. Development testing of fluidflow through assembled valve bodies both with, and without, the sealdisc 12 installed demonstrated a significant improvement of fluid massflow rate with the seal disc 12 installed. Tested assemblies measured anaverage of 20-ml/min. higher flow rate with seal discs installed.

This observation assists in supporting the efficacy of the fluid dynamicproperties of the valve design. It is theorized that differential fluidflow velocities within the valve cavity, sans seal disc, create anappreciable turbulent zone in proximity to the internal “fingers” orprojections on the valve outlet body component. Higher velocity fluidflowing near the longitudinal axis of the valve assembly devoid of theobstruction of the seal disc, meets lower velocity laminar fluid flowconforming to the valve body internal surfaces and flowing between the“finger” projections resulting in turbulence near the convergent sectionof the valve body outlet.

As shown in FIGS. 6-12, both inlet and outlet valve body components aredesigned to incorporate five varieties of standard medical type endconnections: male slip luer, female slip luer, male luer lock, femaleluer lock, and/or straight tube connection.

Each of the end connection configurations is interchangeable betweeninlet and outlet body components, offering 25 different modularcombinations of end connections according to customer needs. Alliterations of valve bodies retain the same basic center section geometryand volume, differing only in the end connections, and all variationsutilize a common valve seal disc.

Series production for various valve body configurations may beaccomplished with interchangeable mold tool inserts where practical,thus offering more cost effective flexibility in manufacturing andfaster response to various customer requirements. Male luer lockconfigurations present specific challenges with respect to the internalthreads of the design and consequently may not be a candidate forinterchangeable tooling, however the balance of the end connectionconfigurations all present themselves as acceptable candidates for themodular tooling concept. Survey of other check valves of this typecurrently in the market, appears to indicate that the male luer lock endconnection is not prevalent at this time. The most prevalent endconnection combination currently on the market is a combination of amale slip luer fitting and straight tube fitting.

The valve design is parametrically scalable and the proportion of valveseal and valve body size can be easily scaled to achieve parity withincreased end connection sizes. This allows a broad range of customerrequired sizes, including unique and non-standard end connectionconfigurations. For example, ISO standard medical type end connectionscurrently in popular clinical use may be employed. The assembled size ofthe valve design is roughly 50% smaller than competitive valves withsimilar flow rates.

Polycarbonate and PVC, (USP class VI), materials are preferably selectedfor the valve body components. Tests with polypropylene resulted inexcessive material shrinkage sufficient to render the male slip luerdimensional tolerances well below limits, and nonfunctional withstandard mating components. While the polypropylene parts were producedon tooling not designed for that material shrinkage, polypropylenematerial may be a poor candidate material for this design, whereas withpolycarbonate and PVC materials yield excellent results in test articlesfor dimensional stability, material strength, and weld ability.

All materials, (polycarbonate, PVC and polypropylene), exhibit excellentweld characteristics. Further refinement of weld parameters, includingthrough analysis and design of optimal weld tooling are anticipated forseries production. Dukane Corporation offers weld tool design analysisand may be consulted as capital assembly equipment is produced. Testweld tooling should be relative to the verified natural vibrationfrequencies of the product assembly and the weld tool, since a durableand consistent manufacturing process will rely heavily on the criticalweld interface integrity of the valve assembly.

Leak and pressure testing of welded valve assemblies demonstratedconsistent weld integrity above 60-psig air. No discernable leaks orbubbles were detected in over 200 consecutively welded valves. Asgravity feed applications average approximately 3 psi and intravenouspump applications specify 20 psi maximum operating pressure capability,this precluded ultimate burst pressure testing subsequent to determiningthat the welded assemblies routinely survived over 60 psi in weldintegrity tests.

Optimal weld parameters with the test tooling and sample prototype partson the Dukane welder were determined to be: TABLE-US-00001 Amplifier:2:1 Weld distance: 0.002 in. Weld dwell time: 1.0 second Ram pressure:30 psig

These weld settings yielded acceptable welds with little or no flash ordistortion and exhibited consistent weld integrity via pressure testing.Destructive examination of welded assemblies further demonstratedacceptable strength of the weld join.

Series production weld parameters may be based on the above values as anominal datum.

C. Parylene Coating:

Parylene “N” is selected as a coating for the silicone and polyisoprenesubstrate seal discs.

The coating serves as dry film lubricant to ensure smooth consistentvalve operation, prevent sticking of the seal disc in the open or closedposition and maintain opening, (crack), pressure of the valve as low aspossible.

Parylene is recognized as a USP Class VI polymer and is gaining wide useand acceptance in medical components and devices. Generically known asparylene, the material called “Parylene N” is polyparaxylylene, a linearcrystalline material. The coating is applied to the substrate by meansof vapor deposition process in a vacuum chamber. Depending on processedload quantities, the Parylene coating adds an average estimated cost of$0.003 per coated component to the manufactured cost. The benefit ofimproved competitive performance makes Parylene an attractive material.Specialized process equipment is required to coat Parylene.

D. Valve Performance Flow and Pressure:

As shown in FIG. 13, valve test assemblies were subjected to flowtesting with unfiltered water at approximately 70 degrees Fahrenheit todetermine fluid mass flow capabilities at approximately 1.0 centipoiseviscosity.

Various valves of similar types, (non-return, or check valve), were alsoflow tested as comparison to validate the design objective of the discvalve of the invention. As is shown in the comparative flow chart, thevalve design exhibited superior mass flow capability to all valvestested thus far. With the exception of the Codan valve, all other valvestested are approximately 100% larger in physical size than the testedembodiment of the invention's design. The stated design goal of thehighest possible flow in the smallest possible valve assembly package isdemonstrated via this comparative analysis.

For the purpose of this comparative flow test, only valves with similarend connection sizes were tested. In the instance of the comparativeflow charted, the valve body configuration of the embodiment of theinvention consisted of a standard 4-millimeter straight tube connectionon the inlet, and a standard ISO male slip luer connection on theoutlet. When larger end connection fitting configurations of the valvebody components are available, additional comparative flow testingshould be undertaken against comparably sized valves from othermanufacturers. Observations of competitive valves indicate, however,that they rely upon larger end connection fittings with little or nochange in their basic valve cavity and seal design size. Competitivevalves generally rely on increased annular diameter to achieve “parity”with their valve assembly's inlet and outlet cross-sectional area torender the maximum possible fluid flow through the valve. This of courseresults in an increased physical size of the assembled valve package, asthis design approach generally relies on the internal wall of the valvebody to maintain the lateral location of the seal. These valve designsalso tend to rely on a traditional flat, thin elastomeric disc toprovide their seal. While these discs are inexpensive and relativelysimple, they often suffer from compression set, or deformation, underhigher differential loads, and are occasionally prone to becomingmisaligned and stuck in an open position.

The valve design closest in flow capability to the design of the presentinvention, (B. Braun #1), utilized a “fixed” flat disc that is impingedat its center point, allowing the disc to deflect from flat to aprogressively sharper conical shape under differential pressure. Thevalve design of the present invention relies on maintaining the annulusformed by the periphery of the valve seal disc and internal wall of thevalve body equal to, or greater than, the cross-sectional area of theinlet and outlet ports of the valve. Additionally, the annular areaformed between the face of the valve seal and the valve body sealinterface in the open position are maintained equal to, or greater than,the valve inlet and outlet individual cross-sectional area of the fluidpath.

The interstitial space between the projections, or “fingers” in thevalve assembly interior are similarly arranged to cumulatively providefluid path area equal to, or greater than, the inlet or outlet. Theshape of the valve body outlet component internal wall forms aconvergent orifice, interrupted circumferentially by the projections,(“fingers”), which forms a smooth transition of fluid flow from betweenthe projections and into the valve outlet. When in the open position,the outside profile of the seal disc occludes a portion of theinterstitial spaces between the projections. The specific shape of thevalve seal disc outer profile, then functions cooperatively with thevalve body internal wall shape to form a core shape within the boundaryof the projections further streamlining the fluid flow path andminimizing cavitation or turbulence by directing the individualinterstitial fluid pathways more directly into the convergent orifice ofthe valve body outlet. Reverse fluid flow entering the valve from theopposite direction of normal intended flow impacts the cupped portion ofthe seal disc while also flowing into the interstitial spaces betweenthe “fingers”. Fluid pressure and velocity at the center of the valveassembly bounded by the projections is higher than that at the peripheryof the internal valve cavity, thus more quickly forcing the valve sealdisc to move axially toward the closed position. In this manner the sealdisc functions like a piston, taking advantage of fluid dynamics tofunction more efficiently.

The present invention includes that contained in the appended claims aswell as that of the foregoing description. Although this description hasbeen described in its preferred form with a certain degree ofparticularity, it should be understood that the present disclosure ofthe preferred form has been made only by way of example and thatnumerous changes in the details of construction, combination, orarrangement of parts thereof may be resorted to without departing fromthe spirit and scope of the invention.

Now that the invention has been described,

1. A valve for controlling the flow of a fluid through a fluid passagesuch that a fluid flow in the fluid passage is permitted in a firstdirection and restricted in a second direction, said valve comprising amodular valve body composed of a two-piece assembly including an inletbody half and an outlet body half joined along a joint interface, saidinlet body half and said outlet body half each comprises interchangeableend connections.
 2. The valve as set forth in claim 1, wherein saidjoint interface is substantially at a midline of said valve.
 3. Thevalve as set forth in claim 2, wherein said midline is substantiallyperpendicular to a center flow axis of the valve.
 4. The valve as setforth in claim 1, wherein said joint interface comprises an overlapping“L” shape.
 5. The valve as set forth in claim 3, wherein saidoverlapping “L” shape of said joint interface is solvent bonded forjoining said inlet body half and said outlet body half along said jointinterface.
 6. The valve as set forth in claim 3, wherein saidoverlapping “L” shape of said joint interface is sonic welded forjoining said inlet body half and said outlet body half along said jointinterface.
 7. The valve as set forth in claim 1, wherein each saidinterchangeable end connection comprises a male slip luer, female slipluer, male luer lock, female luer lock or tube connection.
 8. The valveas set forth in claim 1, wherein each said interchangeable endconnection is selected from the group consisting of a male slip luer,female slip luer, male luer lock, female luer lock and tube connection.9. A method for assembling a modular valve composed of an inlet bodyhalf and an outlet body half joined along a joint interface andenclosing a valve element for controlling the flow of a fluidtherethrough such that a fluid flow is permitted in a first directionand restricted in a second direction, comprises the steps of: providinga supply of the inlet body halves having the same inlet joint interfaceand a variety of end connections; providing a supply of outlet bodyhalves having the same outlet joint interface and a variety of endconnections; wherein said inlet joint interface and said outlet jointinterface are complementarily configured to be joined together; andwherein said end connections comprises a male slip luer, female slipluer, male luer lock, female luer lock or tube connection, whereby avalve having a desired end connection on its input and a desired endconnection on its output may be modularly assembled from the supply ofbody halves.
 10. The method as set forth in claim 9, wherein said jointinterface is substantially at a midline of said valve.
 11. The method asset forth in claim 10, wherein said midline is substantiallyperpendicular to a center flow axis of the valve.
 12. The method as setforth in claim 11, wherein said joint interface comprises an overlapping“L” shape.
 13. The method as set forth in claim 12, wherein saidoverlapping “L” shape of said joint interface is solvent bonded forjoining said inlet body half and said outlet body half along said jointinterface.
 14. The method as set forth in claim 13, wherein saidoverlapping “L” shape of said joint interface is sonic welded forjoining said inlet body half and said outlet body half along said jointinterface.
 15. The method as set forth in claim 9, wherein each saidinterchangeable end connection is selected from the group consisting ofa male slip luer, female slip luer, male luer lock, female luer lock andtube connection.